Electrical connectors used in uncontrolled environments typically are provided with seals to protect the electrically conductive members therein. For example, many electrical connectors are used in environments where ambient moisture, lubricants or other liquids could seep into portions of the connector at which terminals are disposed, thereby damaging these electrically conductive components or degrading the signals they carry. State-of-the-art military equipment often includes electrical connectors which necessarily are used in such uncontrolled environments.
One particular type of electrical connector includes a cable terminated in a connector which in turn is mateable with a connector mounted to a second cable or a panel of an electrical apparatus. The cable may comprise one or more conductors depending upon the particular application. The cable often will be used with a backshell/frontshell combination. For example, the entire cable may be securely mounted to a backshell, with appropriate strain relief and environmental sealing between the cable and the backshell. The backshell typically is formed from an electrically conductive material to ensure electrical grounding across the connector. The forward end of this prior art backshell typically is threadably connected to the rearward end of a frontshell, which in turn is removably mounted to a connector housing. The terminals to which the conductive leads of the cable are joined are appropriately mounted within the connector housing. The connector housing and the terminals therein may then be mated with a corresponding connector mounted to another cable or a panel of an electrical apparatus.
The configuration of the connector housing is dictated by the number and type of terminals to be mounted therein and by the configuration of the electrical apparatus to which the connector is mounted. The configuration of the frontshell is at least in part dictated by the configuration of the connector to which the frontshell is mounted. Many frontshells and their associated connector housings are manufactured to military specifications developed to meet particular military applications. However, many such frontshells and connector housings have been adopted by industries for nonmilitary applications.
The rearwardly facing end of the prior art frontshell has assumed many structural configurations depending upon the particular military specification that has been adopted and followed. For example, some frontshells have a circumferential array of rearwardly projecting serrations, while others have a substantially planar rearward face. Some frontshells have substantially narrow rearwardly facing walls, while others have substantially thick rearwardly facing walls. In all such applications, it is generally desirable to provide environmental sealing between the frontshell and backshell. In the past, the particular configuration of the environmental seal between the frontshell and the backshell has been dependent upon the configuration of the rearwardly facing end of the frontshell. This has created substantial inventory problems and has added to the total cost of the assembly.
The prior art includes a particularly effective seal for mounting in a backshell and for universal use with a plurality of different frontshell configurations. This seal is shown in U.S. Pat. No. 4,707,047 which issued to the applicants herein on Nov. 17, 1987 and which is assigned to the assignee of the subject invention. The disclosure of U.S. Pat. No. 4,707,047 is incorporated herein by reference. Briefly, the backshell shown in U.S. Pat. No. 4,707,047 includes a generally cylindrical rigid outer shell and a coupling portion comprising an array of internal threads adapted to engage external threads on a frontshell. The backshell further comprises a shoulder disposed radially and axially inwardly from the array of internal threads to generally face the frontshell to be mated therewith. The backshell shown in U.S. Pat. No. 4,707,047 further comprises a recess formed at a radial location between the shoulder and the exterior wall of the backshell. The recess extends in axial directions on either side of the shoulder mating surface. The backshell shown in U.S. Pat. No. 4,707,047 further comprises a ring-like resilient gasket of rectangular cross section elongated in a radial direction. The gasket is dimensioned to fit within the recess of the backshell. Thus, the shoulder and the recess cooperate with the gasket to provide environmental sealing with the frontshell threadably engaged to the backshell.
The backshell assembly disclosed in U.S. Pat. No. 4,707,047 provides effective environmental sealing and the extremely desirable attribute of universal applicability to a plurality of different frontshell configurations. However, it has been found that the gasket retaining recess disposed at a radial location between the shoulder and the external wall of the backshell and axially on both sides of the shoulder mating surface can be relatively expensive to machine. More particularly, the machining operation requires the formation of a generally radially outwardly extending annular recess in the wall of the backshell disposed in close proximity to an array of internal threads and extending axially on both sides of the shoulder. This recess has added to both the time and cost associated with the production of the backshell.
In view of the above, it is an object of the subject invention to provide a resilient seal between a backshell and frontshell that permits a relatively easily manufactured and inexpensive backshell construction.
It is a further object of the subject invention to provide an effective universal seal for environmentally sealing the interface between a frontshell and backshell.
It is an additional object of the subject invention to provide a backshell that effectively and securely retains a resilient seal without a recess extending radially outwardly from the shoulder and without extending axially on both sides of the shoulder.
Still another object of the subject invention is to provide enhanced sealing between a frontshell and backshell.
A further object of the subject invention is to provide an efficient molded elastomeric seal that can be securely retained in a backshell and that can be used with a plurality of different frontshell configurations.